EP4037432B1 - Induktionsheizvorrichtung und verfahren zur steuerung einer induktionsheizvorrichtung - Google Patents

Induktionsheizvorrichtung und verfahren zur steuerung einer induktionsheizvorrichtung

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Publication number
EP4037432B1
EP4037432B1 EP22153584.2A EP22153584A EP4037432B1 EP 4037432 B1 EP4037432 B1 EP 4037432B1 EP 22153584 A EP22153584 A EP 22153584A EP 4037432 B1 EP4037432 B1 EP 4037432B1
Authority
EP
European Patent Office
Prior art keywords
inverter circuit
working coil
power value
value
output
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
EP22153584.2A
Other languages
English (en)
French (fr)
Other versions
EP4037432A1 (de
Inventor
Gwangrok Kim
Jung Youn Lee
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
LG Electronics Inc
Original Assignee
LG Electronics Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by LG Electronics Inc filed Critical LG Electronics Inc
Publication of EP4037432A1 publication Critical patent/EP4037432A1/de
Application granted granted Critical
Publication of EP4037432B1 publication Critical patent/EP4037432B1/de
Active legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/10—Induction heating apparatus, other than furnaces, for specific applications
    • H05B6/12—Cooking devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/06—Control, e.g. of temperature, of power
    • H05B6/062—Control, e.g. of temperature, of power for cooking plates or the like
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/10—Induction heating apparatus, other than furnaces, for specific applications
    • H05B6/12—Cooking devices
    • H05B6/1209—Cooking devices induction cooking plates or the like and devices to be used in combination with them
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2206/00—Aspects relating to heating by electric, magnetic, or electromagnetic fields covered by group H05B6/00
    • H05B2206/02—Induction heating
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2213/00—Aspects relating both to resistive heating and to induction heating, covered by H05B3/00 and H05B6/00
    • H05B2213/05—Heating plates with pan detection means

Definitions

  • the present disclosure relates to an induction heating apparatus and a method for controlling the induction heating apparatus.
  • An induction heating apparatus is a mechanism that heats a container by generating an eddy current in a metal container, using a magnetic field generated around a working coil.
  • an alternating current may be applied to the working coil.
  • an induction magnetic field may be generated around the working coil disposed in the induction heating apparatus.
  • a magnetic force line of the induced magnetic field generated in this way passes through the bottom of the container having a metal component placed on the working coil, an eddy current may be generated inside the bottom of the container.
  • the container itself may be heated.
  • AC current for driving a working coil is supplied by an inverter circuit including a plurality of switching elements.
  • the magnitude of the AC current supplied to the working coil varies based on the driving frequency of the inverter circuit.
  • the driving frequency of the inverter circuit is determined based on the required power value of the working coil, and the required power value of the working coil is a value determined based on a power level set for a heating region (or heating area) corresponding to the working coil.
  • the required power value of the working coil corresponding to the set power value is determined.
  • the actual output power value of the working coil has to match the required power value. Therefore, in the process of controlling the induction heating apparatus, it is necessary to measure the output power value of the working coil and adjust the driving frequency of the inverter circuit based on the output power value.
  • Cited document 1 Korean Patent Publication No. 10-2008-0057399 discloses a method and apparatus for controlling an inverter.
  • FIG. 1 is a block diagram illustrating the configuration of the apparatus for controlling the inverter disclosed in Cited document 1.
  • the apparatus for controlling the inverter disclosed in Cited document 1 includes a DC converter 71 supplied DC power, a power circuit 72, a power voltage sensing circuit 73 configured to sense the power voltage supplied through the DC converter 71, a motor 74, an inverter IC (IPM) 75 configured to supply power to power to the motor 74, a shunt resistor 76 configured to detect the current flowing through the inverter IC (IMP) 75 to prevent overcurrent, a comparator 77 configured to compare the voltage Va applied to the shunt resistor 76 with a preset reference voltage Vb, thereby transmitting the result of comparison, a microcomputer 78 configured to output a three-phase power control signal to the inverter IC (IPM) 75 to control the driving of the motor 74 and the driving of other loads based on the comparison result of the comparator 77, and a load drive part 79 configured to drive a load such as a heater 80 based on a control signal of the microcomputer
  • Cited document 1 as shown in FIG. 1 , a control signal is supplied to IC (IPM) 75 to control the driving of the motor and other loads.
  • the control signal is generated based on the result of the comparison between the voltage Va applied to the shunt resistor 76 and the reference voltage Vb.
  • the inverter controlling apparatus has to include not only the shunt resistor 76 for controlling the inverter IC (IPM) and the driving of the load but also the voltage measuring circuit and the current measuring circuit for measuring the voltage and the current applied to the shunt resistor 76.
  • Cited document 2 Korean Patent Publication No. 10-2009-0061863 ), the subject matter of which is incorporated herein by reference, discloses an inverter heating cooker and a method for controlling the same.
  • FIG. 2 is a block diagram illustrating the configuration of the inverter heating cooker (or the induction heating cooker) disclosed in Cited document 2.
  • the inverter heating cooker includes a power source part 81 receiving and supplying commercial power for home use, an IGBT drive part 85, a power element 86, a heating coil 87, an inverter circuit including a resonance capacitor and generating and outputting a resonance voltage for heating food contained in a container or vessel, an input voltage sensor 82, an input current sensor 83, a microcomputer 84 controlling the operation of the induction heating cooker, and a trigger part 88 outputting a trigger signal when the resonance voltage generated in the inverter circuit reaches a preset voltage level.
  • power consumption may be calculated based on the input voltage value detected by the input voltage sensor 82 and the input current detected by the input current sensor 83, and the inverter circuit may be controlled based on the calculated power consumption.
  • an element or circuit e.g., the shunt resistor, the input voltage sensing circuit and the input current sensing circuit
  • an element or circuit is additionally required in order to control the inverter circuit and control the output of the load. Accordingly, the prior art has a disadvantage in that the device configuration is complicated and the manufacturing cost is increased.
  • the output power value of the load or heating coil is not calculated based on the actual voltage value and the actual current input to the load or the heating coil, but the output power value is calculated based on the magnitude of the voltage and current input from the outside. Therefore, it is difficult to calculate an accurate output power value, and accordingly, it is difficult to accurately control the driving of the load or heating coil.
  • the calculation of the output power value and the control of the load or heating coil may be performed based on the detected value using a hardware detection circuit such as the input voltage detection circuit or the input current detection circuit, so that it can be difficult to quickly control the load or heating coil in response to change in the output power value.
  • WO 2019/226019 A1 relates to cooking apparatus and control method thereof.
  • KR 101 832 211 B1 relates to induction heating cookers for magnetic and non-magnetic containers.
  • US 2018/177000 A1 relates to induction heat cooking apparatus and method for operating the same.
  • KR 102 201 189 B1 relates to induction heating device.
  • US 2005/247703 A1 relates to apparatus for controlling inverter circuit of induction heat cooker.
  • An object of the present disclosure is to provide an induction heating apparatus that may calculate the output power value of a working coil and the driving of the working coil only with existing elements or circuits, without additional elements or circuits, and a method for controlling the induction heating apparatus.
  • elements or circuits may include, e.g., a shunt resistor, an input voltage detection circuit and an input current detection circuit.
  • An object of the present disclosure is to provide an induction heating apparatus that may calculate a more accurate output power value based on the actual voltage value and an actual current value to the working coil and control accurate driving of the working coil, and a method for controlling the induction heating apparatus.
  • An object of the present disclosure is to provide an induction apparatus that may improve control speed and responsiveness to changes in the output power value by calculating the output power value of the working coil by using software.
  • an output power value of a working coil may be calculated based on an output voltage of an inverter circuit and an output current of the inverter circuit.
  • the output voltage of the inverter circuit may be calculated based on a DC link voltage value and/or based on a DC link voltage function of the inverter circuit and a switching function of the inverter circuit.
  • the output power value of the working coil may be an integral value of the output voltage function of the inverter circuit calculated based on the DC link voltage value and the output current function of the inverter circuit.
  • Embodiments of the present disclosure may provide a method for controlling an induction heating apparatus, e.g. an induction heating apparatus according to any one of the herein described embodiments, including steps of: receiving a power level for a heating region; supplying a switching signal to an inverter circuit based on a predetermined reference frequency; measuring an output current value of the inverter circuit; measuring a DC link voltage value; calculating an output power value of the working coil based on the output current value of the inverter circuit and the DC link voltage value; determining a heating frequency of the inverter circuit based the result of comparison by comparing the output power value of the working coil with a required power value; and supplying a switching signal to the inverter circuit based on the heating frequency.
  • the output power value of the working coil may be an integral value of the output voltage function of the inverter circuit calculated based on the DC link voltage value and the output current function of the inverter circuit.
  • the DC link voltage may be obtained by rectifying an AC voltage supplied by an external power source and smoothing the rectified voltage.
  • the output voltage function of the inverter circuit may be calculated by combining the DC link voltage function and the switching function of the inverter circuit.
  • VDC (tj) is a DC link voltage function
  • ⁇ ( ⁇ ) is a switching function of the inverter circuit
  • io ( ⁇ ) is an output current function of the inverter circuit
  • T' is a period of the switching function
  • N is the value obtained by driving the period of the DC link voltage function by the period T' of the switching function
  • P is the output power value of the working coil.
  • the step of determining the heating frequency of the inverter circuit based the result of comparison by comparing the output power value of the working coil with a required power value may include steps of adjusting a driving frequency of the inverter circuit until the output power value of the working coil matches the required power value; and determining the driving frequency of the inverter circuit, when the output power value of the working coil matches the required power value, as the heating frequency.
  • Embodiments of the present disclosure may also provide an induction heating apparatus including a working coil provided in a position corresponding to a heating region; an inverter circuit comprising a plurality of switching elements and configured to supply current to the working coil; a drive circuit configured to supply switching signals to the switching elements provided in the inverter circuit, respectively, and a controller configured to determine a driving frequency of the inverter circuit and drive the working coil by supplying a control signal to the drive circuit based on the driving frequency.
  • the controller may be configured to perform a method according to any one of the herein described embodiments.
  • the controller may be configured to receive a power level for a heating region, to supply a switching signal to an inverter circuit based on a predetermined reference frequency, to measure an output current value of the inverter circuit, to measure a DC link voltage value, to calculate an output power value of the working coil based on the output current value of the inverter circuit and the DC link voltage value, to determine a heating frequency of the inverter circuit based the result of comparison by comparing the output power value of the working coil with a required power value, and to supply a switching signal to the inverter circuit based on the heating frequency.
  • the output power value of the working coil may be an integral value of an output voltage function of the inverter circuit calculated, e.g. by the controller, based on the DC link voltage value and an output current function of the inverter circuit.
  • the output voltage function and/or the output current function of the inverter circuit may be stored and/or predetermined for the inverter circuit.
  • the output voltage function of the inverter circuit may be calculated, e.g. by the controller, by combining a DC link voltage function and a switching function of the inverter circuit.
  • the output voltage function of the inverter circuit may be defined based on a combination of a DC link voltage function and a switching function of the inverter circuit.
  • the DC link voltage function and/or the switching function of the inverter circuit may be stored and/or predetermined for the inverter circuit.
  • VDC (tj) is a DC link voltage function
  • ⁇ ( ⁇ ) is a switching function of the inverter circuit
  • io ( ⁇ ) is an output current function of the inverter circuit
  • T' is a period of the switching function
  • N is the value obtained by driving the period of the DC link voltage function by the period T' of the switching function
  • P is the output power value of the working coil.
  • the controller may be configured to adjust a driving frequency of the inverter circuit until the output power value of the working coil matches the required power value, and to determine the driving frequency of the inverter circuit, when the output power value of the working coil matches the required power value, as the heating frequency.
  • control speed of the induction heating device and the responsiveness to changes in the output power value are improved by calculating the output power value of the working coil by using software.
  • FIG. 3 is an exploded perspective diagram illustrating an induction heating apparatus according to one embodiment of the present disclosure.
  • an induction heating apparatus may include a case 102 defining a body thereof and a cover plate 104 coupled to the case 102 and sealing the case 102.
  • the cover plate 104 may be coupled to an upper surface of the case to close the space formed in the case 102 from the outside.
  • the cover plate 104 may include a top plate 106 on which an object to be heated (i.e., a container for cooking food) is placed.
  • the top plate 106 may be made of a tempered glass material such as ceramic glass, but is not limited thereto. The material of the top plate 106 may vary according to embodiments.
  • Heating regions 12 and 14 (or heating areas) corresponding to working coil assemblies 122 and 124, respectively, may be formed in the top plate 106. Lines or figures corresponding to the heating regions 12 and 14 may be printed or displayed on the top plate 106 in order for a user to clearly recognize the positions of the heating regions 12 and 14.
  • the case 102 may have a hexahedral shape with an open top.
  • the working coil assembly 122 and 124 for heating a container or vessel may be disposed in the space formed inside the case 102.
  • an interface unit 114 (or interface) may be provided inside the case 102 and have functions to adjust a power level of each heating region 12 and 14 and display related information to the induction heating apparatus 10.
  • the interface unit 114 may be a touch panel that is capable of both inputting information and displaying information by touch, but the interface unit 114 having a different structure may be provided according to embodiments.
  • a manipulation region 118 may be formed in a position corresponding to the interface unit 114 in the top plate 106.
  • characters or images may be printed on the manipulation region 118.
  • the user may perform a desired operation by touching a specific point of the manipulation region 118 with reference to the characters or images pre-printed on the manipulation region 118.
  • the user may set the power level of each heating region 12 and 14 through the interface unit 114.
  • the power level may be indicated by a number (e.g., 1, 2, 3,..., 9) on the manipulation region 118.
  • the required power value and the heating frequency of the working coil assemblies responding to the respective heating regions 12 and 14 may be determined.
  • a controller may drive each working coil so that the actual output power value can match the required power value set by the user based on the determined heating frequency.
  • a power source part 112 (or power source) for supplying power to the working coil assemblies 122 and 124 or the interface unit 114.
  • two working coil assemblies i.e., a first working coil assembly 122 and a second working coil assembly 1234 are disposed inside the case 102.
  • three or more working coil assemblies may be provided in the case 102 according to embodiments.
  • Each working coil assembly 122 and 124 may include a working coil configured to an induced magnetic field using a high frequency alternating current supplied by the power source part 112, and an insulating sheet configured to protect the coil from heat generated by the container.
  • the first working coil 122 shown in FIG. 3 may include a first working coil 132 for heating the container put in the first heating region 12 and a first insulating sheet 130.
  • the second working coil 124 may include a second working coil and a second insulating sheet. The insulating sheet may not be provided according to embodiments.
  • a temperature sensor 134 may be provided at the center of each working coil.
  • the temperature sensor 134 may be provided in the center of the first working coil 132 as shown in FIG. 3 .
  • the temperature sensor may measure the temperature of the container put in each heating region.
  • the temperature sensor may be a thermistor temperature sensor having a variable resistance of which a resistance value changes according to the temperature of the container, but is not limited thereto.
  • the temperature sensor may output a sensing voltage corresponding to the temperature of the container and the sensing voltage output from the temperature sensor may be transmitted to the controller.
  • the controller may check the temperature of the container based on the magnitude of the sensing voltage output from the temperature sensor.
  • the controller may perform an onverheat protection operation of lowering the actual power value of the working coil or stopping the driving of the working coil.
  • a circuit board on which a plurality of circuits or elements including the controller may be disposed in the space formed inside the case 102.
  • the controller may perform a heating operation by driving each working coil based on the user's heating start command input through the interface unit 114.
  • the controller may stop the driving of the working coil to terminate the heating operation.
  • FIG. 4 is a circuit diagram of an induction heating apparatus according to one embodiment.
  • the induction heating apparatus 10 may include a rectifier circuit 202, a smoothing circuit L1 and C1, an inverter circuit 204, a working coil 132, a controller 2 and a drive circuit 22.
  • Other components may also be provided, as may be discussed below.
  • the rectifier circuit 202 may include a plurality of diodes D1, D2, D3 and D4. As shown in FIG. 4 , the rectifier circuit 202 may be a bridge diode circuit and it may be another type circuit according to embodiments. The rectifier circuit 202 may be configured rectify the AC input voltage supplied from a power source 20, thereby outputting a voltage having a pulsating waveform.
  • the smoothing circuit L1 and C1 may smooth the voltage rectified by the rectifier circuit 202 and output a DC link voltage.
  • the smoothing circuit L1 and C1 may include a first inductor L1 and a DC link capacitor C1.
  • a voltage sensor 212 may sense a magnitude of the voltage output (or voltage value) from the DC link capacitor C1 and transmit the sensed voltage value to the controller 2.
  • a current sensor 214 may sense a magnitude of the current output (or current value) from the inverter circuit 204 and transmit the sensed current value to the controller 2.
  • the controller 2 may perform a protection function for stopping the driving of the working coil by stopping the supply of a control signal to the drive circuit 22.
  • the inverter circuit 204 may include a first switching element SW1, a second switching element SW2, a third switching element SW3 and a fourth switching element SW4.
  • the inverter circuit 204 of the induction heating apparatus 10 may be configured as a full-bridge circuit including four switching elements SW1, SW2, SW3 and SW4.
  • the inverter circuit 204 may be configured as a half-bridge circuit including two switching elements (e.g., a first switching element SW1 and a second switching element SW2 as shown in FIG. 4 ).
  • the first switching element SW1, the second switching element SW2, the third switching element SW3 and the fourth switching element SW4 may be turned on and off by a first switching signal S1, a second switching signal S2, a third switching signal S3 and a fourth switching signal S4, respectively.
  • Each of the switching elements SW1, SW2, SW3 and SW4 may be turned on when each of the switching signals S1, S2, S3 and S4 is at a high level, and each of the switching elements SW1, SW2, SW3 and SW4 may be turned off when each of the switching signals S1, S2, S3 and S4 is at a low level.
  • each of the switching elements SW1, SW2, SW3, and SW4 is an IGBT element, but each of the switching elements SW1, SW2, SW3 and SW4 may be a different type of a switching elements (e.g., BJT or FET, etc) according to embodiments.
  • any of the switching elements SW1, SW2, SW3 and SW4 may be turned on and off to complement each other.
  • the second switching element SW2 may be turned off (turned on) while the first switching element SW1 is turned on (turned off).
  • the switching elements that are turned on and off complementary to each other may be referred to as switching elements 'complementary to each other'.
  • any of the switching elements SW1, SW2, SW3 and SW4 may be turned on and off in the same manner as each other.
  • the first switching element SW1 may be turned on and off at the same timing as that of the third switching element SW3.
  • the switching elements that are turned on and off at the same timing may be referred to as the switching elements 'belonging to the same group'.
  • the first switching element SW1 and the third switching element SW3 may be referred to as the switching elements belonging to a first group (i.e., a high side), and the second switching element SW2 and the fourth switching element SW4 may be referred to as the switching elements belonging to a second group (i.e., a low side).
  • the inverter circuit 204 is configured as a half-bridge circuit(i.e., a circuit including only the first switching element SW1 and the second switching element SW2), the first switching element SW1 may belongs to the first group and the second switching element SW2 may belong to the second group.
  • the DC link voltage input to the inverter circuit 204 may be converted into the AC link voltage by the turned-on and turned-off (i.e., the switching operation) of the switching elements SW1, SW2, SW3 and SW4 provided in the inverter circuit 204.
  • the AC current converted by the inverter circuit 204 may be supplied to the working coil 132. As a resonance phenomenon occurs in the working coil 132, an eddy current may flow through the container (or vessel), thereby heating the container (or vessel).
  • the first switching signal S1, the second switching signal S2, the third switching signal S3 and the fourth switching signal S4 may be pulse width modulation (PWM) signals each having a predetermined duty cycle.
  • PWM pulse width modulation
  • the working coil 132 When the AC current output from the inverter circuit 204 is supplied to the working coil 132, the working coil 132 may be driven. While eddy current flows through the container provided on the working coil, with the driving of the working coil 132, the container may be heated. The amount of thermal energy supplied to the container may vary based on the amount of power actually generated by the driving of the working coil, that is, the actual output power value of the working coil.
  • the input power source may supply power to the induction heating apparatus 10 and the induction heating apparatus may enter a driving standby state.
  • the user may put a container on the working coil and set a power level for the container to input a heating start command for the working coil.
  • a power value required for the working coil that is, a required power value may be determined based on the power level set by the user.
  • the controller 2 having received the heating start command from the user may determine a frequency corresponding to the required power value of the working coil 132, that is, a heating frequency, and supply a control signal corresponding to the determined heating frequency to the drive circuit 22. Accordingly, switching signals S1, S2, S3 and S4 may be output from the drive circuit 22. As the switching signals S1, S2, S3 and S4 are input to the switching elements SW1, SW2, SW3 and SW4, respectively, the working coil 132 may be driven. Once the working coil 132 is driven, an eddy current may flow through the container and the container may be heated.
  • the controller 2 may determine a heating frequency corresponding to the power level set for the heating region. For example, when the user sets a power level (or power value) for the heating region, the controller 2 may gradually lower the driving frequency of the inverter circuit 204 until the output power value of the working coil 132 in a state where the driving frequency of the inverter circuit 204 is set to a predetermined reference frequency matches the required power value corresponding to the power level set by the user. The controller 2 may determine a frequency detected when the output power value of the working coil 132 matches the required power value as the heating frequency.
  • the controller 2 may supply a control signal corresponding to the determined heating frequency to the drive circuit 22.
  • the drive circuit 22 may output switching signals S1, S2, S3 and S4 having a duty ratio corresponding to the heating frequency determined by the controller 2 based on the control signal output from the controller 2. While the switching elements SW1, SW2, SW3 and SW4 are turned on and off complementary to each other in response to the input of the switching signals S1, S2, S3 and S4, the alternating current may be supplied to the working coil 132.
  • the controller 2 may calculate the output power value of the working coil 132 based on the magnitude of the output voltage of the DC link capacitor C1 measured by the voltage sensor 212, that is, the DC link voltage value, and the magnitude of the output current of the inverter circuit 204 measured by the current sensor 214, that is, the inverter based on the output current value of the inverter circuit 204.
  • the magnitude of the voltage input to the working coil 132 and the magnitude of the current input to the working coil 132 may be required.
  • the magnitude of the current input to the working coil 132 may be substantially equal to the magnitude of the current output from the inverter circuit 204, that is, the output current value of the inverter circuit 204.
  • the magnitude of the voltage input to the working coil 132 may be substantially equal to the magnitude of the voltage output from the inverter circuit 204, that is, the output voltage value of the inverter circuit 204.
  • the output voltage value of the inverter circuit 204 may be calculated based on a DC link voltage function or a switching function of the inverter circuit 204.
  • FIG. is a graph illustrating a DC link voltage function of an inverter circuit according to one embodiment.
  • FIG. 6 is a graph illustrating a switching function of the inverter circuit according to one embodiment.
  • FIG. 7 is a graph illustrating the result of combining the DC link voltage function shown in FIG. 5 and the switching function of the inverter circuit shown in FIG. 6 .
  • the controller 2 may measure the DC link voltage value through the voltage sensor 212.
  • the controller 2 may calculate the DC link voltage function based on the measured DC link voltage value as shown in FIG. 5 .
  • the controller 2 may calculate the output voltage value of the inverter circuit 204 by using a predetermined switching function of the inverter circuit 204.
  • the switching function of the inverter circuit 204 may be a function representing a voltage level supplied from the inverter circuit 204 to the working coil 132 based on the combination of the switching signals supplied to the inverter circuit 204.
  • the switching function may be predetermined during the manufacturing process of the induction heating apparatus 10 and stored in a storage. Accordingly, the controller 2 may refer to a pre-stored switching function.
  • the switching function shown in FIG. 6 may be a function having a period (T').
  • the period T' of the switching function shown in FIG. 5 may be smaller than the period T of the DC link voltage function.
  • the period T' of the switching function may repeatedly appear within one period T of the DC link voltage function.
  • FIG. 7 is a graph illustrating the result of combining the DC link voltage function shown in FIG. 5 and the switching function of the inverter circuit 204 shown in FIG. 6 .
  • V DC represents the magnitude of the DC link voltage.
  • the magnitude V DC of the DC link voltage may be directly reflected in the waveform of the switching function of the inverter circuit 204.
  • the result of combining the DC link voltage function and the switching function of the inverter circuit 204 may be considered to be substantially the same as the output voltage of the inverter circuit 204. Accordingly, the controller 2 may calculate the output power value of the working coil 132 based on the output current function based on the result of combining the DC link function and the switching function of the inverter circuit 204 and the output current value of the inverter circuit 204 measured by the current sensor 214.
  • T is the period of the DC link voltage function.
  • V o (t) is a function of the output voltage of the inverter circuit 204 and i o (t) is a function of the output current of the inverter circuit 204.
  • V DC (t) represents a DC link voltage function
  • ⁇ (t) represents a switching function of the inverter circuit 204.
  • V DC (t j ) is a DC link voltage function
  • ⁇ ( ⁇ ) is a switching function of the inverter circuit 204
  • Io ( ⁇ ) is an output current function of the inverter circuit 204.
  • T' is the period of the switching function
  • N is the value obtained by driving the period T of the DC link voltage function by the period T' of the switching function.
  • the output power value of the working coil 132 may be defined as an integral value of the output voltage function of the inverter circuit calculated based on the DC link voltage value and the output current function of the inverter circuit.
  • the controller 2 may calculate the output voltage value of the working coil 2 in real time and in software based on [Equation 3].
  • the output voltage value of the working coil 132 during the driving of the working coil 132 may be calculated quickly and accurately. Since the output voltage value of the working coil 132 is calculated quickly and accurately, the heating operation of the working coil 132 may be controlled more precisely.
  • the control response to the change in the output voltage value of the working coil 132 may be accelerated, so that the control speed of the induction heating apparatus may be improved.
  • FIG. 8 is a flow chart illustrating a method for controlling the induction heating apparatus according to one embodiment of the present disclosure.
  • the controller 2 may receive a power level (or power value) for the heating region (or heating area) input through the interface unit 114 (402). Once the power level for the heating region is input, a required power value corresponding to the input power level may be determined.
  • the controller 2 may supply a control signal to the drive circuit 22 based on a preset reference frequency (e.g., 60kHz) and then supply a switching signal to the inverter circuit 204 (404). Accordingly, the working coil 132 may start to output power corresponding to the reference frequency.
  • a preset reference frequency e.g. 60kHz
  • the controller 2 may measure the output current value of the inverter circuit 204 through the current sensor 214 (406). The controller 2 may calculate an output current function of the inverter circuit 204 based on the measured output current value of the inverter circuit 204.
  • the controller 2 may measure a DC link voltage value through the voltage sensor 212 (408). The controller may calculate a DC link voltage function based on the measured DC link voltage value.
  • the controller 2 may calculate the output power value of the working coil 132 based on the output current value of the inverter circuit 204 and the DC link voltage value (410).
  • the output power value of the working coil 132 may be defined as an integral value of the output voltage function of the inverter circuit calculated based on the DC link voltage value and the output current function of the inverter circuit. Additionally, the output voltage function of the inverter circuit 204 may be calculated by combining the DC link voltage function and the switching function of the inverter circuit.
  • the controller 2 may calculate the output power value of the working coil 132 based on [Equation 3].
  • the controller 2 may compare the calculated output power value with the required power value, and determine the heating frequency of the inverter circuit 204 based on the result of the comparison (412).
  • the step of determining the heating frequency (412) may include a step of adjusting the driving frequency of the inverter circuit 204 until the output power value of the working coil 132 matches the required power value, and a step of determining the driving frequency of the inverter circuit 204 when the output power value of the working coil 132 matches the required power value as the heating frequency.
  • the controller 2 may supply a control signal to the drive circuit 22 based on the heating frequency and supply a switching signal to the inverter circuit 204 (414). Accordingly, the working coil 132 may output power corresponding to the power level, thereby heating the container.
  • FIG. 9 is a flow chart illustrating a method for controlling the induction heating apparatus according to another embodiment of the present disclosure.
  • the controller 2 may receive a power level for the heating region input through the interface unit 114 (602). Once the power level for the heating region is input, a required power value corresponding to the input power level may be determined.
  • the controller 2 may set the driving frequency of the inverter circuit 204 to be a preset reference frequency (e.g., 60kHz) (604).
  • the size of the reference frequency may vary according to embodiments.
  • the controller 2 may supply a control signal to the drive circuit 22 based on the preset reference frequency and then supply a switching signal to the inverter circuit 204 (606). Accordingly, the working coil 132 may start to output power corresponding to the reference frequency.
  • the controller 2 may measure the output current value of the inverter circuit 204 through the current sensor 214 (608). The controller 2 may calculate an output current function of the inverter circuit 204 based on the measured output current value of the inverter circuit 204.
  • the controller 2 may measure a DC link voltage value through the voltage sensor 212 (610). The controller may calculate a DC link voltage function based on the measured DC link voltage value.
  • the controller 2 may calculate the output power value of the working coil 132 based on the output current value of the inverter circuit 204 and the DC link voltage value (612).
  • the output power value of the working coil 132 may be defined as an integral value of the output voltage function of the inverter circuit calculated based on the DC link voltage value and the output current function of the inverter circuit.
  • the output voltage function of the inverter circuit 204 may be calculated by combining the DC link voltage function and the switching function of the inverter circuit.
  • the controller 2 may calculate the output power value of the working coil 132 based on [Equation 3].
  • the controller 2 may compare the calculated output power value with the required power value, and determine the heating frequency of the inverter circuit 204 based on the result of the comparison (614).
  • the controller 2 may reduce the driving frequency of the inverter circuit 204 by a predetermined unit size (e.g., 1 kHz) (616), and return to the step (606). Accordingly, the driving frequency of the inverter circuit 204 may be reduced until the output power value matches the required power value.
  • a predetermined unit size e.g. 1 kHz
  • the controller may determine the current driving frequency of the inverter circuit 204 as the heating frequency (618) and set the driving frequency of the inverter circuit 204 as the heating frequency (620). Once determining the heating frequency, the controller may supply switching signals to the inverter circuit 204 by supplying the control signals to the drive circuit 22 based on the heating frequency (622). Accordingly, the working coil 132 may heat the container by outputting power corresponding to the power level.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • General Induction Heating (AREA)
  • Inverter Devices (AREA)
  • Induction Heating Cooking Devices (AREA)

Claims (10)

  1. Verfahren zum Steuern einer Induktionsheizvorrichtung, die eine Wechselrichterschaltung (204) und eine Arbeitsspule (132) enthält, wobei das Verfahren die folgenden Schritte umfasst:
    Empfangen (402, 602) eines Leistungspegels für einen Heizbereich;
    Zuführen (404, 606) eines Schaltsignals zu der Wechselrichterschaltung basierend auf einer vorgegebenen Referenzfrequenz;
    Messen (406, 608) eines Ausgangsstromwerts der Wechselrichterschaltung;
    Messen (408, 610) eines Gleichstrom-Zwischenkreisspannungswertes;
    Berechnen (410, 612) eines Ausgangsleistungswertes der Arbeitsspule basierend auf dem Ausgangsstromwert der Wechselrichterschaltung und des Zwischenkreisspannungswertes;
    Bestimmen (412, 618) einer Heizfrequenz der Wechselrichterschaltung basierend auf dem Ergebnis des Vergleichs durch Vergleichen des berechneten Ausgangsleistungswertes der Arbeitsspule mit einem erforderlichen Leistungswert; und
    Zuführen (414, 622) eines Schaltsignals zu der Wechselrichterschaltung basierend auf der Heizfrequenz,
    dadurch gekennzeichnet, dass der Ausgangsleistungswert der Arbeitsspule basierend auf der folgenden Gleichung berechnet wird: P = 1 N ∑ j = 1 N v DC t j T ′ ∫ t j − 1 t j Ψ τ i o τ dτ ,
    wobei VDC(tj) eine Gleichstromverbindungsstreckenspannungsfunktion ist und ψ(τ) eine Schaltfunktion der Wechselrichterschaltung ist, und i0(τ) eine Ausgangsstromfunktion der Wechselrichterspannung ist, und T' eine Periode der Schaltfunktion ist, und N der Wert ist, der durch Ansteuern der Periode der Gleichstromverbindungsstreckenspannungsfunktion durch die Periode T' der Schaltfunktion erhalten wird, und P der Ausgangsleistungswert der Arbeitsspule ist.
  2. Verfahren zum Steuern der Induktionsheizvorrichtung nach Anspruch 1, wobei der Schritt des Bestimmens der Heizfrequenz der Wechselrichterschaltung basierend auf dem Ergebnis des Vergleichs durch Vergleichen des Ausgangsleistungswertes der Arbeitsspule mit einem erforderlichen Leistungswert (412) die folgenden Schritte umfasst:
    Anpassen (616) einer Ansteuerfrequenz der Wechselrichterschaltung, bis der Ausgangsleistungswert der Arbeitsspule mit dem erforderlichen Leistungswert übereinstimmt.
  3. Verfahren zum Steuern der Induktionsheizvorrichtung nach einem der vorhergehenden Ansprüche, wobei eine Ansteuerfrequenz der Wechselrichterschaltung verringert oder erhöht wird, wenn das Ergebnis des Vergleichs anzeigt, dass der berechnete Ausgangsleistungswert nicht mit dem erforderlichen Leistungswert übereinstimmt.
  4. Verfahren zum Steuern der Induktionsheizvorrichtung nach einem der vorhergehenden Ansprüche, wobei eine Ansteuerfrequenz der Wechselrichterschaltung beibehalten wird, wenn der berechnete Ausgangsleistungswert mit dem erforderlichen Leistungswert übereinstimmt.
  5. Verfahren zum Steuern der Induktionsheizvorrichtung nach einem der vorhergehenden Ansprüche, das ferner Folgendes umfasst:
    Bestimmen (620) der Ansteuerfrequenz der Wechselrichterschaltung als die Heizfrequenz, wenn der Ausgangsleistungswert der Arbeitsspule mit dem erforderlichen Leistungswert übereinstimmt.
  6. Verfahren zum Steuern der Induktionsheizvorrichtung nach einem der vorhergehenden Ansprüche, wobei die Ansteuerfrequenz der Wechselrichterschaltung auf die vordefinierte Referenzfrequenz eingestellt wird, wenn der Leistungspegel empfangen wird.
  7. Induktionsheizvorrichtung, die Folgendes umfasst:
    eine Arbeitsspule (132), die in einer Position, die einem Heizbereich entspricht, vorgesehen ist;
    eine Wechselrichterschaltung (204), die mehrere Schaltelemente (SW1, ..., SW4) umfasst und konfiguriert ist, der Arbeitsspule (132) Strom zuzuführen;
    eine Ansteuerschaltung (22), die konfiguriert ist, den Schaltelementen (SW1, ..., SW4), die in der Wechselrichterschaltung (204) vorgesehen sind, jeweils Schaltsignale zuzuführen, und
    eine Steuereinrichtung (2), die konfiguriert ist, eine Ansteuerfrequenz der Wechselrichtungsschaltung (204) zu bestimmen und die Arbeitsspule (132) anzusteuern, durch Zuführen eines Steuersignals zu der Ansteuerschaltung (22) basierend auf der Ansteuerfrequenz,
    dadurch gekennzeichnet, dass die Steuereinrichtung konfiguriert ist, ein Verfahren nach einem der vorhergehenden Ansprüche durchzuführen.
  8. Induktionsheizvorrichtung nach Anspruch 7, die ferner Folgendes umfasst:
    eine Gleichrichterschaltung (202) zum Gleichrichten einer Wechselstromeingangsspannung, die von einer Leistungsquelle (20) zugeführt wird; und
    eine Glättungsschaltung (L1, C1) zum Glätten der Spannung, die durch die Gleichrichterschaltung gleichgerichtet worden ist, und Ausgeben der Gleichstrom-Zwischenkreisspannung.
  9. Induktionsheizvorrichtung nach Anspruch 8, wobei die Glättungsschaltung (L1, C1) eine erste Induktivität (L1) und einen Gleichstromzwischenkreis-Kondensator (C1) enthält.
  10. Induktionsheizvorrichtung nach einem der Ansprüche 7 bis 9, die ferner Folgendes umfasst:
    einen Stromsensor (214) zum Erfassen eines Stromwerts des Stroms, der von der Wechselrichterschaltung (204) ausgegeben worden ist, und Bereitstellen des Spannungswertes für die Steuereinrichtung (2); und/oder
    einen Spannungssensor (212) zum Erfassen eines Spannungswertes, der von dem Gleichstromzwischenkreis-Kondensator (C1) ausgegeben worden ist, und Bereitstellen des Stromwertes für die Steuereinrichtung (2).
EP22153584.2A 2021-01-27 2022-01-27 Induktionsheizvorrichtung und verfahren zur steuerung einer induktionsheizvorrichtung Active EP4037432B1 (de)

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US5111014A (en) 1988-06-14 1992-05-05 Kabushiki Kaisha Toshiba Electromagnetic cooker including load control
JP3244348B2 (ja) 1993-07-01 2002-01-07 オリンパス光学工業株式会社 測距装置
KR20050103704A (ko) * 2004-04-27 2005-11-01 엘지전자 주식회사 유도가열 조리기기의 인버터 회로 제어장치
KR20080057399A (ko) 2006-12-20 2008-06-25 엘지전자 주식회사 인버터 제어장치 및 방법
KR100904235B1 (ko) 2007-12-12 2009-06-25 주식회사 부방테크론 유도가열 조리기 및 이의 제어 방법
KR20180069532A (ko) 2016-12-15 2018-06-25 엘지전자 주식회사 전자 유도 가열 조리기 및 그의 동작 방법
KR101832211B1 (ko) * 2017-06-15 2018-02-26 주식회사 아미크론 자성 및 비자성 용기 겸용 유도가열 조리기
KR102557394B1 (ko) * 2018-05-25 2023-07-19 삼성전자주식회사 조리장치 및 그 제어방법
KR102620662B1 (ko) 2018-10-18 2024-01-04 삼성전자주식회사 조리 기기 및 이의 제어 방법
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